Protector.



P. B. ERIKSON. PROTECTOR.

APPLICATION FILED MAR- 13, 1909.

063,249. Patented Jung3,1913.

7 UN T PER. ERIKSON, NEW YORK,

ET FFI@E.

OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

PROTECTOR.

Specification of Letters Patent.

Patented June 3, 1913.

Application filed March 16, 1909. seria1No,4s3,s45.

To all whom it may concern.-

Be it known that 1, PER E. ERIKSON, a subject of the King of Sweden, and a resident of New York. in the county of New York and State of New York, have invented a certain new and useful Improvement in Protectors, of which the following is a full,

clear, concise, and exact description.

My invention relates to protectors for electrical circuits, more particularly to protectors of the type adapted to provide a ground connection for a line circuit when its potential 1s raised to an abnormal or dangerous degree. A well known form ofprotector of the type mentioned comprises two confronting discharge plates adapted to be serially connected in a grounded branch of a circuit, said discharge plates being separated by an air gap so adjusted that when the potential. of the circuitapproaches a dangerous degree, the air in the gap breaks down and affords a discharge path to earth. Protectors of this type have heretofore proved objectionable in that the discharge current leaves the plates fused together, or otherwise bridged, thereby permanently grounding the line and interfering with the normal operation of the circuit until said plates are renewed, repaired or re-adjusted. In cases where the-protector is located at a remote point, as, for example, at the subscribers station of a telephone line, any attention which the device may require, involves inconvenience and maintenance expense. I I have been able to provide a pro tector which is free from these objections by my discovery that if'one of the confronting plates be of metal and the other be'of an alloy of said metal, a discharge across the gap leaves the device unaffected, thereby obviating the necessity of repalr, ad ustment or other attention when the discharge occurs. y

My invention will be more readily understood by reference to the accompanylng drawings, in which Figural is plan view of a protector comprising discharge plates of'my invention? Said view showing the protector with the coVeFremoved; Fig. 2 is a side elevation, partly insection', of, said protector; and F 1g 3 is a diagram showing the mode of connection of my protector with a line circuit.

Similar letters of reference designate similar parts throughout the various figures.

Referringto Figs. 1 and 2, I have chosen to illustrate my invention as it might be embodied in a protector of well known type, designed particularly for use at the subscribers station of a telephone line. In the structure referred to, 4 is a base of porcelain on which a central vertical ground plate 5 is mounted. said plate being electrically connected with a binding post 6. On either side of the plate 5 vertical. line springs 7 and S are mounted, said springs being electrically connected with binding posts 9 and 10, respectively. Between the ground plate 5 and the line springs 7 and 8, discharge plates 11 and 12 are frictionally held. said plates being separated by astrip 1.; of mica or other material having suitable dielectric properties. and said strip being formed with an opening to provide an air gap in a manner well understood by those skilled in the art. Pins let and 15 are mounted in plates 12 and extend through the mica strip 13 into rubber bushings 16 and 17. respectively, as a means of holding the parts in proper relative position.

In Fig. 3 I have shown a pair of line wires 18 and 19 and have illustrated the mode of connection of the discharge plates therewith. as they would ordinarily be connected at any point of a circuit where it may be desired to introduce the protector.

In the preferred form of my invention I make one discharge plate of each pair of copper, and the confronting plate of a brass constituted of a fifty per cent. alloy of copper and zinc, which combination I have found particularly well adapted to resist the tendency of the arc to fuse the opposing surfaces together. or otherwise form a conductive bridge. I do not, however,- wish to be understood as limiting my invention to the materials or proportions specified. Nor do I limit my invention to the use of discharge plates, the entire body of either of which is of uniform composition, since its advantages might obviously be realized by the use of plates of various materials, having their confronting faces coated or covered with materials having properties cliaracteristic' of my discovery.

Having described my invention, I claim: A' protector for electrical circuits comprising two discharge plates, one being of copper and the other of an alloy of copger,

thin sheet of insulating material havmg an opening therethrough located between said plates; and means for clam lin'g said 10 plates and sheet together. I

In witness whereof, I, hereunto subscribe my name this 15th day of March A. D., 1909.

I PER E. ERIKSON.

Witnesses 'RUsH F. NEWCOMB, IRVING MACDONALD. 

